Madrid Hospital Saves a Patient's Leg With a 3D-Printed Titanium Metamaterial Bone Implant

A titanium implant that mimics bone instead of replacing it

Surgeons at Madrid's Gregorio Marañón Hospital have implanted what they say is the world's first personalized metamaterial bone prosthesis, built with metal 3D printing and designed to imitate the mechanical behavior of natural bone. The implant let a 38-year-old patient avoid amputation and start walking again within a year.

The patient, Pierre Chazel, was diagnosed with a high-grade bone sarcoma in his tibia. After an infection and severe bone density loss, the remaining bone could not support a conventional implant. Standard prostheses are solid metal pieces sized by the surgeon. This one was calculated from Chazel's own radiological images.

Engineers at the Polytechnic University of Madrid (UPM) built a digital twin of his healthy leg and simulated the loads the tibia endures during walking, climbing stairs, and stumbling. That data drove the internal architecture of the implant: a lattice of millimeter-scale titanium rods arranged to distribute weight the way healthy bone does.

The result weighs 300 grams and withstands more than 500 kilograms of force. A conventional titanium prosthesis of similar function can weigh several kilograms and typically supports 100 to 150 kilograms. The lighter weight matters, but the bigger advantage is how the structure interacts with living tissue. The titanium lattice encourages the patient's own bone to grow into the implant, reducing rejection risk and helping the surrounding tissue stay healthy instead of weakening from disuse.

Why this matters for more than one patient

The hospital has already completed a second implant and is preparing two more personalized devices, one for a wrist and another for a sternum. The goal is to offer this hyper-personalized approach through Spain's public health system.

The cost is also striking. A typical custom implant of this complexity costs between 30,000 and 50,000 euros. The 3D-printed version cost roughly 3,000 euros, mostly the price of the titanium powder and printing time. That gap suggests these devices could scale beyond single cases in major research hospitals.

Amputation was the alternative for Chazel. A year after surgery he is walking without crutches. The implant survived a serious fall during rehabilitation intact. That real-world test is a stronger endorsement than any lab simulation.